Method and Device for Transmitting Binary Data

1. A method, in a transmitter, for transmitting binary data using a M-ASK (Amplitude-Shift Keying) constellation divided into M/2 sets of two symbols, each set of index i comprising the ith and ith+M/2 symbols of the M-ASK constellation, where iϵ[1;M/2], and being associated with a probability pi of transmitting the first symbol of the set and a probability 1−pi of transmitting the second symbol of the set and wherein each symbol of the M-ASK constellation is associated with a binary word defined using natural labelling, said method comprising: a) obtaining m−1 bits from an equiprobable binary source where m=log2M; b) selecting a binary source in a plurality of binary sources responsive to said m−1 bits, each binary source of index i being associated with a probability of outputting a bit zero equal to pi; c) obtaining one bit from the selected source; d) obtaining a symbol of the M-ASK constellation associated with the binary word formed by the m−1 bits as less significant bits and the bit obtained from the selected source as most significant bit; e) transmitting said obtained symbol to a receiver over a communication channel.

2. The method according to claim 1, wherein selecting the binary source in a plurality of binary sources responsive to said m−1 bits comprises—: determining a decimal value of a binary sequence formed by the m−1 bits; and selecting the binary source whose index equal said decimal value incremented by one.

3. The method according to claim 1 wherein the plurality of binary sources comprises 2m−1 binary sources.

4. The method according to claim 3, wherein,, p i = 1 - p M 2 - i + 1 , 1 ≤ i ≤ M 4 ,, the plurality of binary sources is reduced to 2m−2 binary sources and wherein selecting a binary source responsive to said m−1 bits comprises: determining a decimal value D of a binary sequence formed by the m−1 bits; and selecting the binary source whose index equal M/2−D in the case where, M 4 + 1 ≤ D + 1 ≤ M 2 ;, and selecting the binary source whose index equal said decimal value incremented by one, otherwise;, and wherein, in the case where the binary source whose index equal M/2−D is selected, the bit obtained from the selected source is flipped before obtaining a symbol of the M-ASK constellation.

5. The method according to claim 1, wherein each binary source of index i in the plurality of binary sources is obtained from the equiprobable binary source by applying binary distribution matching on sequences of, r S ⁢ max ⁢ H ⁡ ( p i ), bits, where Smax is the number of sources in the plurality of binary sources, H(pi) denotes a binary entropy with probability pi and r being an integer greater than or equal to 1.

6. The method according to claim 1, further comprising—: encoding r times (m−1)*k bits obtained from the equiprobable binary source using an error correcting code into (m−1)*n bits, where n and k are integers; obtaining each binary source of index i in the plurality of binary sources from the equiprobable binary source by applying binary distribution matching on sequences of, r * n S ⁢ max ⁢ H ⁡ ( p i ), bits obtained from the equiprobable binary source, where Smax is the number of sources in the plurality of binary sources and H(pi) denotes the binary entropy with probability pi; and applying a) to e) on each of the n sets of (m−1) bits—.

7. The method according to claim 5, further comprising obtaining the probabilities pi from a table and transmitting to said receiver at least one index entry indicating the obtained probabilities.

8. The method according to claim 5, further comprising estimating the probabilities pi from a predefined communication channel distribution and transmitting said estimated probabilities to said receiver.

9. The method according to claim 5, further comprising receiving the probabilities pi from the receiver.

10. A transmitter configured to transmit binary data using a M-ASK (Amplitude-Shift Keying) constellation divided into M/2 sets of two symbols, each set of index i comprising the ith and ith+M/2 symbols of the M-ASK constellation, where iϵ[1;M/2], and being associated with a probability pi of transmitting the first symbol of the set and wherein each symbol of the M-ASK constellation is associated with a binary word defined using natural labelling, said transmitter comprising at least one processor configured to: a) obtain m−1 bits from an equiprobable binary source where m=log2M; b) select a binary source in a plurality of binary sources responsive to said m−1 bits, each binary source of index i being associated with a probability of outputting a bit zero equal to pi; c) obtain one bit from the selected source; d) obtain a symbol of the M-ASK constellation associated with the binary word formed by the m−1 bits as less significant bits and the bit obtained from the selected source as most significant bit; e) transmit said obtained symbol to a receiver over a communication channel.

11. A non-transitory computer readable storage medium storing program code instructions, the program code instructions causing implementation of the method according to claim 1 when the program code instructions are read from the non-transitory computer readable storage medium and run by a programmable device.